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公开(公告)号：US20190195688A1
公开(公告)日：2019-06-27
申请号：US16229355
申请日：2018-12-21
CPC分类号： G01J3/0229 , G01J3/10 , G01J3/18 , G01J3/2803 , G01J3/44 , G01N21/65 , G01N2201/06113 , G01N2201/0635 , G01N2201/0638
摘要： In swept source Raman (SSR) spectroscopy, a swept laser beam illuminates a sample, which inelastically scatters some of the incident light. This inelastically scattered light is shifted in wavelength by an amount called the Raman shift. The Raman-shifted light can be measured with a fixed spectrally selective filter and a detector. The Raman spectrum can be obtained by sweeping the wavelength of the excitation source and, therefore, the Raman shift. The resolution of the Raman spectrum is determined by the filter bandwidth and the frequency resolution of the swept source. An SSR spectrometer can be smaller, more sensitive, and less expensive than a conventional Raman spectrometer because it uses a tunable laser and a fixed filter instead of free-space propagation for spectral separation. Its sensitivity depends on the size of the collection optics. And it can use a nonlinearly swept laser beam thanks to a wavemeter that measures the beam's absolute wavelength during Raman spectrum acquisition.
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公开(公告)号：US20210208470A1
公开(公告)日：2021-07-08
申请号：US17091905
申请日：2020-11-06
摘要： Optical read-out of a cryogenic device (such as a superconducting logic or detector element) can be performed with a forward-biased optical modulator that is directly coupled to the cryogenic device without any intervening electrical amplifier. Forward-biasing at cryogenic temperatures enables very high modulation efficiency (1,000-10,000 pm/V) of the optical modulator, and allows for optical modulation with millivolt driving signals and microwatt power dissipation in the cryogenic environment. Modulated optical signals can be coupled out of the cryostat via an optical fiber, reducing the thermal load on the cryostat. Using optical fiber instead of electrical wires can increase the communication bandwidth between the cryogenic environment and room-temperature environment to bandwidth densities as high as Tbps/mm2 using wavelength division multiplexing. Sensitive optical signals having higher robustness to noise and crosstalk, because of their immunity to electromagnetic interference, can be carried by the optical fiber.
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公开(公告)号：US20220034715A1
公开(公告)日：2022-02-03
申请号：US17335299
申请日：2021-06-01
申请人： Rajeev J. RAM , Amir H. Atabaki , Nili Persits , Jaehwan Kim
发明人： Rajeev J. RAM , Amir H. Atabaki , Nili Persits , Jaehwan Kim
摘要： Swept-source Raman spectroscopy uses a tunable laser and a fixed-wavelength detector instead of a spectrometer or interferometer to perform Raman spectroscopy with the throughput advantage of Fourier transform Raman spectroscopy without bulky optics or moving mirrors. Although the tunable laser can be larger and more costly than a fixed wavelength diode laser used in other Raman systems, it is possible to split and switch the laser light to multiple ports simultaneously and/or sequentially. Each site can be monitored by its own fixed-wavelength detector. This architecture can be scaled by cascading fiber switches and/or couplers between the tunable laser and measurement sites. By multiplexing measurements at different sites, it is possible to monitor many sites at once. Moreover, each site can be meters to kilometers from the tunable laser. This makes it possible to perform swept-source Raman spectroscopy at many points across a continuous flow manufacturing environment with a single laser.
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公开(公告)号：US20210091252A1
公开(公告)日：2021-03-25
申请号：US17032223
申请日：2020-09-25
IPC分类号： H01L31/105 , H01L31/0368
摘要： Photodetectors using photonic crystals (PhCs) in polysilicon film that include an in-plane resonant defect. A biatomic photodetector includes an optical defect mode that is confined from all directions in the plane of the PhC by the photonic bandgap structure. The coupling of the resonance (or defect) mode to out-of-plane radiation can be adjusted by the design of the defect. Further, a “guided-mode resonance” (GMR) photodetector provides in-plane resonance through a second-order grating effect in the PhC. Absorption of an illumination field can be enhanced through this resonance.
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